Tadalafil has not been studied with other medicines used for treatment of erectile dysfunction. Using them together is not recommended .

It is important that you tell all of your healthcare providers that you take tadalafil. If you need emergency medical care for a heart problem, it is important that your healthcare provider knows when you last took tadalafil.

If you experience a prolonged or painful erection for 4 hours or more, contact your doctor immediately. This condition may require prompt medical treatment to prevent serious and permanent damage to your penis.

CIALIS does not protect you against sexually transmitted diseases. Use protective measures and ask your doctor if you have any questions about this.

It is important to tell your doctor about any heart problems you may have now or may have had in the past. CIALIS can cause serious side effects in patients with heart problems.

Do not drink alcohol to excess (for example, 5 glasses of wine or 5 shots of whiskey) when taking tadalafil. When taken in excess alcohol can increase your chances of getting a headache or getting dizzy, increasing your heart rate, or lowering your blood pressure.

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur:

• Less common
  • Arm, back or jaw pain;  blurred vision ;  chest pain or discomfort;  chest tightness or heaviness;  chills;  cold sweats;  confusion;  dizziness;  fainting;  faintness, or lightheadedness when getting up from a lying or sitting position suddenly;  fast or irregular heartbeat;  headache;  nausea;  nervousness;  pain or discomfort in arms, jaw, back or neck;  pounding in the ears;  shortness of breath;  slow or fast heartbeat;  sweating;  unusual tiredness or weakness ;  vomiting 
  
  

• Rare
  • Painful or prolonged erection of the penis 
  
  

Other side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. However, check with your doctor if any of the following side effects continue or are bothersome.

• More Common
  • Acid or sour stomach;  belching;  heartburn;  indigestion;  stomach discomfort, upset, or pain 
  
  

• Less common
  • Bloody nose;  burning, crawling, itching, numbness, prickling, "pins and needles" , or tingling feelings;  burning feeling in chest or stomach;  burning, dry or itching eyes;  body aches or pain ;  congestion;  cough;  diarrhea;  difficulty in moving;  difficulty swallowing;  dry mouth;  dryness or soreness of throat;  eye pain ;  excessive eye discharge;  fever;  feeling of constant movement of self or surroundings ;  feeling of warmth redness of the face, neck, arms and occasionally, upper chest;  hoarseness;  increased erection;  itching skin;  joint pain;  lack or loss of strength ;  loose stools;  muscle aching or cramping;  muscle pains or stiffness;  nasal congestion;  neck pain;  pain;  pain in arms and/or legs;  pain or burning in throat;  rash;  redness, pain, swelling of eye, eyelid, or inner lining of eyelid ;  reduced sensitivity to touch;  runny nose;  sensation of spinning;  sleepiness or unusual drowsiness;  sleeplessness;  sores, ulcers, or white spots on lips or tongue or inside the mouth;  spontaneous penile erection;  stomach upset;  swelling of eyelids;  swelling or puffiness of eye or face;  swollen joints;  tearing;  tender, swollen glands in neck;  tenderness in stomach area;  trouble sleeping;  unable to sleep;  upper abdominal pain;  voice changes;  watering of eyes 
  
  

Other side effects not listed above may also occur in some patients. If you notice any other effects, check with your doctor.

• Rare
  • Changes in color vision